ErfurtWiki
ErfurtWiki is a small Wiki engine implemented in PHP which stores its pages in a MySQL database or via a flat file backend. The Wiki source parsing is rather complete but is very extensible. It stands out from other Wikis in that it does not define the whole page layout itself; instead it allows for very quick integration into an existing Web site. The whole 'library' is fully contained in one script file. Additionally, it can cache referenced images. The simplicity of the image uploading function makes it also a good choice as lite CMS for private homepages.